Method for optical brightening of polymeric substrates utilizing 2-styryloxazole compounds



United States Patent METHOD FOR OPTICAL BRIGHTENING OF POLY- MERIC SUBSTRATES UTILIZING 2-STYRYLOX- AZOLE COMPOUNDS Ichiro Okubo and Michihiro Tsujimoto, Tokyo, Japan, assignors to Mitsui Kagalru Kogyo Kabushiki Kaisha, Tokyo, Japan No Drawing. Original application Aug. 31, 1962, Ser. No. 220,904, new Patent No. 3,262,929, dated July 26, 1966. Divided and this application Oct. 22, 1965, Ser. No. 502,414 Claims priority, application Japan, Sept. 12, 1961,

36/33,.302, 36/33,303; July 21, 1962, 37/29,641 21 Claims. (Cl. 11733.5)

ABSTRACT OF THE DISCLOSURE This invention relates to methods for optical brightening utilizing certain novel Z-styryloxazole compounds. The methods are particularly applicable to organic fibrous materials, especially of synthetic nature, aqueous dispersions of the compounds, together with dispersing aids being suitable. The said compounds may be either benzoxazoles or napthoxazoles and various substituents may be present in their molecular structures. Some of the compounds are found to be especially superior and certain fibrous materials are notably benefited.

This application is a division of our prior application Ser. No. 220,904, now Patent No. 3,262,929.

This invention relates to methods of optical brightening utilizing novel Z-styryloxazole compounds.

It is an object of this invention to provide new and useful methods for o tical brightening of organic fibrous materials.

The novel 2-styryl0xazole compounds of this invention have the structure represented by the general formula:

wherein A is a member selected from the group consisting of substituted benzene rings and unsubstituted naphthalene ring, which is condensed with the oxazole ring, substitutes of said benzene rings being selected from the group consisting of -alkyl-, aryl, and alkylene-groups, and R and R are selected from hydrogen, halogen, cyano group, carboxyl group and its ester residue, alkyl group and aryl group.

2-styryloxazole compounds were little known in the past, although, for example, 2-styrylbenzoxazole and 2- (4'-dimethyla-minostyryl)-benzoxazole were ifound- (D. M. Brown, A. R. Kon, J. Chem. Soc., 1948, 2147).

The present inventors have synthesized a number of 2- styryloxazole compounds to study precisely on their properties, and have found that the novel 2-styryloxazole c0mpounds having the general Formula I exhibit a strong fluorescence and produce an excellent optical brightening effect when organic fibrous materials are treated with these novel compounds. That is, the novel Z-styryl-oxazole compounds are very useful substances as the optical brightening agent for organic fibrous materials, particularly various man-made fibers, and light-fastness is excellent.

The novel 2-styryloxazole compounds of this invention can be prepared by condensation under dehydration of a 3,347,594 Patented Oct. 17, 1967 ice Z-methyloxazole compound represented by the following general formula:

A I O-CHa (wherein A is the same as that in the general Formula I), with a benz'aldehyde derivative represented by the following general formula:

. R III (wherein R and R are the same as those in the general Formula I).

Alternatively the compounds of this invention can be prepared by intra-molecular ring closure under dehydration of a novel ciunamic acid-(O-oxyaryD-amide derivative represented by general formula:

0 ll NH IV (wherein A, R and R are the same as those in the general Formula I).

The following compounds can be cited as examples of 2-methyloxazole compound of the general Formula II among the starting materials employed for preparin the novel 2-styryloxazole compounds of this invention! Z-methylbenzoxaz-ole 2,5-dimethylbenzoxazole 2,5 ,7-trimethylbenzoxazole 2-methyl-4,5 -cyc1otetramethylenebenzoxazole 2-methyl-5-ethylbenzoxazo1e 2-methyl-5-isopropylbenzoxazole Z-methyl-S-terhbutylbenzoxazole Z-methyl-S-phenylbenzoxazole Z-methyI-S-acetylaminobenzoxazole 2-methyl-a-naphthox'azole Z-methyl-fl-naphthoxazole and the like.

And also the following compounds can be cited as examples of benzaldehyde derivative of the general Formula III among the starting materials:

The condensation reaction under dehydration of 2- methyloxazole compound of the general Formula II with benzaldehyde derivative of the general Formula 111 can be carried out by taking the both starting materials at about equal molar ratio and heating at -200 C. by adding or not adding a dehydrating agent.

3 4 Among the starting material, cinnamic acid-(O-oxycinnamic acid chloride aryl)-amide derivative can be easily obtained by N 3-chlorocinnamic acid chloride acylating O-aminophenols or O-aminonaphthols, for 4-chlorocinnamic acid chloride example, 4-cyano-3-chlorocinnamic acid chloride 4-methyl-2-amin0phen0l 5 according to a conventional method. The intra-molecular mBthyl:2-arnin0phenOl ring closure reaction under dehydration of cinnamic acidy f p (O-oxyaryl)-arnide thus obtained can be carried out in 4cphiiflyl-z-ammophenol an inert organic solvent such as xylene, chlorobenzene, lamfnc'z'naphthol 10 dichlorobenzene and the like by adding a dehydrating z'ammo'l'naphthol and the like agent and causing a reaction by heating. or their inorganic acid salts with cinnamic acid halogen- The examples of novel 2-styryloxazole compounds .Of ide, for example, this invention are shown in Table 1.

TABLE 1 Fluorescence No. Structural Formula Property and melting point in benzene solution 1- O Colorless needle-like crystals, 154 Violet.

CCH=HC-Cl 0H;

2- 0 Light yellow pillar-like crystals, 196- D0.

Slightly yellow plate crystals, 146- D0.

4 0 Light yellow pillar-like crystals, Do.

\ 310 C. /CGH=HC-COOH 5 O Colorless needle-like crystals, 141- Do.

c-cn=nocoooim Hie 6 0 Cl Light yellow needle-like crystals, VDo.

C--CH=HC 0N mo 7 i 0 C1 Light yellow needle-like crystals, 155+ Do.

con=rrocn H O 8 0 01 Light yellow needle-like crystals, 260- Blue.

268 0. CCH=HC -COOH H3O 9 Slightly yellow needle-like crystals Blue-violet.

slllggig-thite flake-like crystals, 134- Violet.

TABLE '1Con tlnued Fluorescence No. Structural Formulav Property and melting point 7 in benzene solution 11 O\ Lilgglg ygallow needle-like crystals, 184- Blue-violet.

COH=HC-CN s 12 o 1 Light yellow pillar-like crystals, 295- D0.

I 297 0. l CCH=HG-COOH (013930 N 13 /O\ 1 Colorless flake-like crystals, Mfr-176C, Violet-blue,

/C-CH=HCCN 14 Colorlessflake-llke crystals, 124-125 C Bluc-vlo1et.

15 Slightly yellow pillar-like crystals, Blue.

CCH==HC 16 0 Light yellow pillar-llke crystals, 122- Green-blue.

17 0 Cl Slightly yellow needle-like crystals, Blue-green.

C-CH=HC 18 O\ Cl 7 Lilgllgg %ellow flake-like crystals, 114- Blue.

U N j 19 Yellow needle-Ilka crystals, 159-160" C. Green-blue,

TABLE '1Continued Fluorescence No. Structural Formula Property and melting point in benzene solution 20 ,Llght yellow.plllarrllkecrystals,125 Violet-blue.

21 O Greenlsh yellow pillar-like crystals, Blue-green.

I /CCH=HC Br U N 22 0 Light yellowflake-llkecrystels, 123 Violet-blue.

/o-on=no .om N

23 0 Yellow long flake-like crystals, Blue.

C-CH=HO-COOH U As shown in Table 1, the novel 2-styryloxazole compounds of this invention have fluorescence of blue violet to violet, and also show excellent affinity toorganic fibrous materials from its aqueous dispersed system so that they are very useful for optical brightening of manmade fibers, particularly polyester, polyacrylonitrile, polyamide, acetalized polyvinyl alcohol, polyolefin and cellulose acetate fibers and their light fastness is remarkable. For example, the compound No. 18 in Table 1 is made into aqueous dispersed system by using anionic surface active agent of alkylbenzene sulfonic acid type, and when the above-mentioned man-made fibers are treated in a treating bath which, is prepared in sucha way as the amount of this compound is 0.1% or 0.2% to the material to be treated, an excellentoptical brightening effect can be obtained. The treating conditions and the light fastness (according to H8 L 10454959, xenon light source) of man-made fibers in this case. are shown in Table 2.

It is convenient to use a composition which is previously mixed with a surface active agent in order to treat organic fibrousmaterials :by using the compound of this invention. For example, a composition comprising parts of Z-styryloxazole compound of this invention,

10 parts of surface active agent of alkyl benzene sulfonic acid type, and 80. parts of formaldehyde; condensate of naphthalene sulfonic acid can be conveniently used.

The process for preparing 2-styryloxazolecompounds of this invention and the method of optical brightening of organic fibrous materials by using such compounds are illustrated, by the, following examples. Percents and parts' herein areby weight.

EXAMPLE 1' EXAMPLE 2 2,5 dimethylbenzoxazole (14.7parts), 4 cyano- 3 chlorobenzaldehyde (18 parts) and. zinc bromide (13 parts) are thoroughly mixed and are caused. to reaction at C. for 6 hours with stirring. In this case the water formed by the reaction is successively driven out of the reaction system. The reactants are boiled and dissolved in 50 parts of methanol. On cooling the methanol solution, 5 methyl-2-(4'-cyano-3-chlorostyryl)-benzoxaz01e is precipitated as yellow crystals..When recrystallized from dirnethyl formarnide, light yellow needle-like crystals (M.P. 221 CI) are obtained.

EXAMPLE 3 2,5,7 trimethylbenzoxazole (16.1 parts), 4 cyanobenzaldehyde (13.1 parts) and zinc chloride (7 parts) are mixed thoroughly and are caused to react at 160-200" C. for 8 hours with stirring while the formed water is successively taken out of the reaction system. Then, the reactants are subjected to steam distillation and unreacted starting materials are distilled out. The distillation residue is treated with hot xylene and the resulting xylene solution is allowed to cool to precipitate 5,7-dimethy1-2-(4'- cyanostyryl)-benzoxazole as yellow needle like crystals. When recrystallized from ligroin containing benzene, slightly yellow needle-like crystals (M.P. 207209 C.) are obtained.

EXAMPLE 4 Z-methyI-a-naphthoxazole (18.3 parts), benzaldehyde (11 parts) and zinc chloride (7 parts) are thoroughly mixed and are caused to react at 160-200 C. for 8 hours with stirring. To the reaction product is added methanol of 3 times volume at hot state and after cooling the precipitate is filtered out. The precipitate is recrystallized from a mixture of ethanol and glacial acetic acid to give light yellow pillar-like crystals (M.P. 300 C.). This one is a double salt of 2-styryl-a-naphthoxazole and zinc chloride. On heating with water, 2-styryl-tx-naphthoxazole is easily separated. Recrystallization from ligroin gives colorless needle-like crystals (M.P. 124125 C.).

EXAMPLE 5 Z-methyl-fi-naphthoxazole (28 parts), 3-chlorobenzaldehyde (22 parts) and zinc chloride parts) are mixed and are caused to react at 160-165 C. for 6 hours while the formed water is successively taken out of the reaction system. The reactants are dissolved in 150 parts of isopropanol. The isopropanol solution is allowed to cool to precipitate 2-(3'-chlorostyryl)-fi-naphthoxazole as yellow crystals. Recrystallization from methanol gives light yellow flake-like crystals (M.P. 1l41l5 0.).

EXAMPLE 6 Cinnamic acid (2'-oxynaphthyl-1') amide obtained from l-amino-Z-naphthol hydrochloric acid salt (20 parts) and cinnamic acid chloride (17 parts) is boiled with 10 part-s of phosphor oxychloride in 50 parts of O- dichlorobenzene for 8 hours while water formed by the reaction is successively distilled out of the system. Then, O-dichlorobenzene is taken out by steam distillation and the distillation residue is treated with ligroin. The ligroin solution is allowed to cool to precipitate Z-styryl-fi-naphthoxazole as yellow crystals. Recrystallization from ligroin gives light yellow pillar-like crystals (M.P. 12l.5-123 C.).

EXAMPLE 7 One part of 2 (4'-cyanostyryl)-5,7-dimethylbenzoxazole of the following formula:

is thoroughly mixed with 9 parts of surface active agent of alkylbenzene sulfonic acid type to give a sample, and 0.2 part of the sample thus prepared per 10 parts of the polyester cloth to be treated is put into 400 parts of water to give a dispersed system. In this dispersed system the polyester cloth is treated at 120 C. for 45 minutes. The treated cloth is washed with water and dried to give the remarkable brightening effect as compared with nontreated cloth.

wherein A is a member selected from the group consisting of substituted benzene rings and an unsubstituted naphthalene ring, A being condensed with the oxazole ring, substituents of said benzene rings being selected from the group consisting of alkyl-, aryl-, and alkylene-groups, and, when A is said unsubstituted naphthalene ring, R and R are selected from hydrogemhalogen, cyano group, carboxyl group and its ester residue, alkyl group and aryl group, R being a cyano group when A is said benzene ring with R being selected as aforesaid, said treating being effected by contacting the said materials with anaqueous dispersion containing said oxazole in an amount suflicient to impart optical brightening effects to the material undergoing treatment. r

2. A method as claimed in claim 1 wherein A of said formula is a benzene ring having at least one alkyl group as the substituent.

3. A method as claimed in claim 1 wherein the said compound is 5-methyl-2-(3'-chloro-4'cyanostyryl)-benzoxazole having the formula:

5. A method as claimed in claim 1 wherein the said compound is 5-ethyl-2-(3'-chloro-4-cyanostyryl)-benzoxazole having the formula:

/0\ 01 .H=OH@ .N

6. A method as claimed in claim 1 wherein the said compound is.

5-methyl-2- (4-cyanostyryl) -b enzoxazole having the formula:

7. A method as claimed in claim 1 wherein the said compound is S-methyl-Z-(4'-carboxyethoxystyryl)-benzoxazole having the formula:

8. A method as claimed in claim 1 wherein A is a naphthalene ring.

1 1 9. A method as claimed in claim 1 wherein said compound is 2-(3-chlorostyryl)-;8-naphthoxoazole having the formula:

10. A method .as claimed =in:.claim 11 wherein-said compound vis 2-(4-'chlorostyryl)-}3 naphthoxazole having the formula:

11.- A method as claimedin claim l'wherein said compound is 2-(3' chlorostyryl)u-naphthoxazole having the.

formula:

12. A method as claimed in claim 1 wherein said compound is 2-(2'-chlorostyryl)-a-naphthoxazole having the formula:

13. A method as claimed in claim l'wherein said compound is 2-(4'-fluorostyryl)-/8-naphthoxazole having the.

formula:

14. A method'as claimedinclaiml'whereinA of said formula is. a benzene ringhaving an alkylene group as the suhstituent.

15. A method as claimed in claim 1 wherein said compound is 4,S-cyclotetramethylene-Z-(4-cyanostyryl)-benzoxazolehaving the formula:

16-. A'method as claimed in .claim- 1 wherein A is a benzene ring having an aryl groupasthe substituent.

17. A method as claimed in claim 1 wherein said compound is S-phenyl-Z-(4'-cyanostyryl)-benzoxazole having the formula:

18. A method as claimed in claiml wherein said. com-, pound is 5-phenyl-2-styrylbenzoxazole having the formula:

19. A method as claimed in claim 1 wherein said com: pound is Zetyryl-fi-naphthoxazole having the formula:

References Cited i UNITED. STATES PATENTS 2,639,282 5/1953 I Sprague et'al. 260-2409 X 3,120,520 2/1964 Buell 117--33.5 3,158,610 11/1964 Buell- 117 -335 FOREIGN PATENTS 578,303 6/1959 Canada. 669,402 4/ 1952 Great, Britain.

WILLIAM D. MARTIN, Primary Examiner.

T. G. DAVIS, AssistanrvExaminer. 

1. A METHOD FOR OPTICAL BRIGHTENING OF SOLID POLYMERIC MATERIALS COMPRISING TREATING SAID MATERIALS WITH AN OXAZOLE COMPOUND OF THE FORMULA 